Ctjrt l



C, L. E, MUELLER.

SPARK PLUG.

APPLHATION FILED JULY i4, i917.

.Patented Dec. 30, 1919.

@argl y UNITED srafrns rarnrrr crimen CUR'I L. E. MUELLER, 0F JOLIET, ILLINOIS, ASSIGNOR 'IO THE CHALLENGE SPARK .PLUG COMPANY, OF JOLIET, ILLINOIS, A CORPORATION 0F ILLINOIS.

SPARK-PLUG.

Leashes.

To all diwm t may concern.'

Be it known that I, CURT L. E. MUELLER, a citizen of the United States, residing at Joliet, in the county of W ill and State of Illinois, have invented a new and useful Improvement in Spark-Plugs, of which the following is a specification.

My invention relates more particularly to improvement in spark-plugs used in internal combustion engines for igniting the charges for driving the engine.

My primary objects are 4to provide a Aspark-plug ofA such construction that upon each suction stroke of the engine air will be drawn into the cylinders above the istons therein, through the spark-plug, pre erably to perform the double function of driving from the upper end of the cylinderl above the piston therein when at the limit of its upwardstroke and from the interior of the spark-plug, burnt gases, which, if allowed to accumulate, especially during the successive operations of the pistons, result in the formation of carbon deposits on the piston cylinder and the exposed parts of the spark-plug, and seriously impair operation of the engine; another object is to provide for forcing from the inner end of the sparkplug,- partieles of carbon which may have become deposited thereon; another object is to still further provide against the accumulation of carbon in the spark-plug, by agitation of one of the electrodes of the plug; another object is to provide improved means whereby the operator may readily determine whether or not the ignition'circuit is dead or ,is short-circuited, and to provide for the intensification of the ignition spark; and other objects as will appear from the following description:

Referring to the accompany drawing- Figure l is a view in vertical sectional elevation of a spark-plug constructed in accordance with my invention and provided with spark-intensifying means and shortcircuit detecting means inaccordance with my invention; Fig. 2 is a section taken at the line 2 on Fig. l and viewed in the direction of the arrow; Fig. 3 is a broken section taken at the line 3 on Fig. 1 and viewed in the direction of the arrow; and Fig. 4, a view in elevation, partly sectional,

Specification of Letters Patent.

Application led July 14, 1,917. Serial No. 180,536.

of a modification of one of the ,electrodes of the plug.

Referring to the construction illustrated in Figs. 1, 2 and 3, 5 represents the usual metal shell adapted to be screwed at its threaded yportion t3 into the spark-plug opening of a cylinder above the piston therein, the lower, inner end of this shell being provided with an electrode 7, which isin electrical connection with the shell 5, lcommonly grounded through its connection with the cylinder of the engine.' Extending into thel shell 5 and resting against a seat 8 therein, having a soft metal facing 9, is a member 10 of porcelain or other material non-conductive of electric current, this member 10 being held rigidly to the shell 5 by means of a .plug l1 surrounding the member 10 and screwing into the upper threaded end of the shell 5. IThe member 10 contains a bore 12 extending longitudinally therethrough -at its central portion, with an enlargement 13 at its lower end forming With the portion 12 a shoulder lll. 'A metal tube 15 is located in the bore 12, this tube interlocking at its headed portion 16, which is disposed in the portion 13 of the bore 12, and extending at its upper threaded end 17 through the upper end of the member l0. Surmounting the member 10 and screwed upon the portion 17 of the tube 15, is a pair of metal nuts 18 and 19, the nut 18 serving to hold the tube 15 and member l0 in assembled relation and these two nuts, in the case of the particular construction illustrated, serving to clamp to the sl'iark-plug a spark-intensifying and short-circuit detecting device hereinafter referred to` but which when this device is not used, ma) serve as albiuding post for connection with one of the terminals of the sparking circuit, the other being grounded on the engine and thus in .electrical connection withl the electrode 7. The other electrode of the sparkplug is represented at 20, this electrode extending atits lower end into close proximity to the electrode 7, in accordance withicommon practice. In the particular construction now being described this electrode, which may be of any suitable current-conducting the member 2O being of such diameter rela-' 33 in this valve, and thus is' in and causes air tive to the diameter of the passage 21 that desirable clearance between these parts :tor the passage of air downwardly through the tube 15, as hereinafter described, may be eected.

Surmounting thenut 19 is an inwardly opening valve device 22, formed of a casing 23, whichisscrewed upon the threaded reduced portion 24 of the nut 19 and contains a valve-seat erating with said stem 27 through a washer 28, between which and a wall 29 of the valve casing in which the seat is located, a' coil-spring 30, surrounding the stem 27, is coniined. The washer 28, which contains openings 32, and is held'onthe stein 27 by' means of a nut 31 screwing upon the upper end of the stein 27, is tree to slide in the valve casing and thus the spring 30 tends to seatithe valve 26. The electrode member 20 in this construction is rigidly connected with'thevalve proper 26, as b-y securing it at its upper end in a socket electrical connection with the member 19.

In the operation of the engine equipped withthe spark-plug, the suction produced 1n the cylinder of the engine upon its suctionv stroke, causes suction to be exerted upon the valve-equipped passage in the spark-plug through the valve-casing 23, passage 21 and `into the cylinder of the engine,

the valve 26 automatically opening in this operation, and the electrode 20 lowering with the valve, the valve 26 immediatelyyclosing as' soon as the suction action ceases in the cylinder. lt will "thus be understood that each time the engine l moves onits'suction stroke air will be drawn ing the burnt into the cylinder above the piston, through the spark-plug, with Vthe result of 'displacgases in the lower end of the sparklug and in the upper end or" the cylinder resulting from previous explosions, thus minimizing the accumulation of carbon in the spark-plug and the upper end ot the cylinder, and cooling the lower end oi the spark-plug to prevent premature ignition; and further avoiding objectionable accumulation of carbon in the spark-plug by the reciprocable movement of the electrode 20, which tends to break up carbonv deposits in the plug. v 'i v The spark-intensifying and short-circuit detecting device hereinbeiore referred to is represented at 34, and is constructed as follows: It is formed of atube 35 of insulating material encircled by ay strap 86 oicurrent conducting material, the ends 37 of which are clamped between the nuts4 18, 19, the tube 17 extending through openings in the ends ot this strap. The strap 36 has screwed therein a screw-pin 38, which tends into a radially disposed socket 39 in the member 35. rlhe memher is provided 25, and a valve proper 26 cop-v seat and extending at its,

to lo'w from the atmosphereV v:member 35 and being adapted to be screwed to a position in the member 35 in which it contacts with the binding post 4l.

rllhe terminal of the sparking circuit other than the one 4which is grounded would be connected with the binding post 40 and thusv through the tube 42, pin 38, strap 36 and nuts 18 and 19, electrically connected with the electrode 20, the screw. 38 being adjustable in the opening 39 for producing a gap betweenthe rod 42 and this screw, when it' is' desired to intensify the spark to be produced at the space between the electrodes 7 and 20. ln the use of the construction as shown,

the current would pass from the binding post 40, thence to the rod 42, which may be adjusted relative to the ypost 41 to present an intensifying spark-gap, 'if desirable, thence to the pin 38, across the gap between it and the rod 42if the adjustment is such as to 4 spark is desired, thence through the sleeve 36, nut 19, valve device 22, electrode 20, across the spark-gap between this electrode 'produce such a gap and intensification of the and the electrode 7 to the shell 5, where it is By adjusting the member 42 away from Grounded and connects with the other the binding post 41, the operator may readily determine, first, whether or not any current is passing through the spark-plug, and, secon ly, short-circuited. This may be determined by observing whether` or not the spark will jump a predetermined gap between the binding post 41 and the rod 42. To simplify this observation, l prefer to provide two openings, 4.4 and 45, extending diametrically through the member 35 and so positioned whether or not the spark-plug is i that when the ,operator rotates the rod 42 to a position in which its extremity, which opposes the binding post 41, is exposed to view in the opening 44, the gap between the post 41 and rod 42 would be of such length that if the normal amount of current is being supplied to the plug, regardless of short-circuit in the plug, the current would jump this gap and would indicate that current is pass ing through the plug; and when this rod is adjusted to a position in which its said 4eniis tremity is exposed to view through the opening 45, -this gap will be of such lengtlrthat the current will not jump it unless the sparkplug is shortcircuited- It will be understood 'from the 'foregoing that the operator may thus readily determine whether or not current is passin through the spark-plug and whether pr n 't it is short-circuitedand means of introducing a priming medium into the cylinder of the engine, as forexample, for use in starting, the said medium being poured into the -upper end of the valve-casing 23, the operator, if desired, de-

pressing the valve 26 to permit of the flow.

i of the medium into the cylinder or this inzov troduction being automatic, if desired, by the suction action of the engine in cranking,

It desired the intensification at the pin 38 may be supplemented by a spark-gap precluded between the post A11 and the rod 115.' Furthermore the manner of connecting the detecting device with the plug permits of the proper positioning of this device about the axis of the plug, to permit of its con-v` nection with the spapigking terminal regardless of the positioito which the plug screws into the cylinder.

The construction illustrated in Fig. 4 is the same, except that the electrode 20, in.

stead of being reciprocable and connected with the valve 26, as shown and explained of the preceding construction, is secured to the lower end of the tube 15, as indicated 4G, in which case it would be in electrical y connection with the binding post members 18 and 19 through the medium of the tube 15, and the opening 21 in the tube 15 would preferably be smaller than in the case of the preceding construction. v A

While I have illustrated and described two forms in which my invention may be embodied, I do not wish to be understood as intending to limit it thereto, as the same may be variously modified and altered Without departing from the spirit of my invention, it being my intention to claim my invention as fullyy and completely as the prior state of the art will permit.

What I regard as new and desire to secure by Letters Patent is:

1. A spark-plug containing an air-passage for communication of the interior of the cylinder of an engine equipped therewith, with the atmosphere, and through which air is drawn into the cylinder of the engine upon the suction stroke of the engine,

a check valve in the outer end. of said passage operating .to permitair to be drawn through said passage and into the cylinder, spring means for normally holding said valve closed, and a rod of current-conduct-` ing material forming one of the sparking electrodes'of the plug, operatively :connected with said valve for movement with the latter and extending inwardly from the valve loosely in said passage and reciprocable in the latter with said valve.

2. A spark-plug containing an air-passage for communication of the interior of the cylinder of an-engine equipped therewith, with the atmosphere, and through which air is drawn into the cylinder of the i i. engine upon the suction stroke of the .en-

gine, a valve in thev outer end of said passage operating to permit air tobe drawn through said passage and into the cylinder, spring means for normally holding said valve closed, and a rod of current-conduct- Iing vmaterial forming one of the sparking i electrodes of the plug, operatively connected with said valve for movement with the latter and extending inwardly from the valve loosely in said passage and reciprocable in the latter with said valve.

oURT L. Ef MUELLnn. 

